Read in the datasheet:
Sleep Mode of the HVD231
The unique difference between the SN65HVD230 and the SN65HVD231 is that both driver and receiver are
switched off in the SN65HVD231 when a logic high is applied to RS (pin 8). The device remains in a very low
power-sleep mode until the circuit is reactivated with a logic low applied to RS (pin 8). While in this sleep mode,
the bus-pins are in a high-impedance state, while the D and R pins default to a logic high.
Question!
Are the D and R pins active high ( driven ) or are they passive high ( pull-up, R output tri-stated ) - with other words, can I use the D-net and the R-net for other signals?
br
lars